A theme park is a permanent outdoor area with rides and attractions that's decorated around a unifying idea. When your family visits a Wild West theme park, you might buy matching cowboy hats as souvenirs.
Theme parks are amusement parks with a common theme. If you visit one, you'll find roller coasters, log rides, bumper cars, Ferris wheels, restaurants, and shops all based on one idea, like the world of the Harry Potter books. You may be familiar with Disney's Magic Kingdom, Legoland, or Universal Studios theme parks, but there are hundreds of others, including South Korea's Imsil Cheese Theme Park and Malta's Popeye Village.